The present invention relates to the field of antennas and more particularly to an antenna arrangement to be provided in the interior of a portable communication device and a portable communication device with such an antenna arrangement.
There is a trend within the field of portable communicating devices, and especially within the field of cellular phones to have the antenna in-built in the phone itself. At the same time there is often a need for several frequency bands for such phones. The reasons for providing different frequency bands are several. First of all some networks provide several frequency bands in order to better distribute traffic in the network. GSM does for instance provide two separate bands that can be used. There are also different types of networks in different countries that use different frequency bands.
It is not a simple task to provide an antenna structure that can be used with good efficiency in several such bands, especially if the antenna is to be based on a PIFA antenna and provided in a stick type phone.
Various methods have been developed to achieve the additional bandwidth such as using parasitic elements that can be end coupled or side coupled, capacitively fed structures, ultra-high structures and electrically matched structures.
Parasitic elements can be useful in achieving additional bandwidth. They may be end coupled or coupled with parallel elements. When end coupling is used, it is necessary to have the space for two elements, which essentially doubles the required antenna volume. It has also been noted, particularly at low-band frequencies, that there is a tendency when parasitic elements are used for a low-gain region to occur in the frequencies between the resonant frequencies of the two resonators.
Several capacitively fed structures have been proposed. These structures can, in general, achieve the required bandwidth, but generally with a reduction in efficiency. When the bandwidth for instance at the low GSM band is doubled, a reduction in gain of 2–3 dB has generally been observed.
Ultra-high structures (13–15 mm in height) have shown promise in some Japanese products. The main problem with these devices is that they cause the overall size of the product to grow to what is often an unacceptable level.
Electrically matched structures have promise in theory. Currently there are a number of ways of accomplishing this, each with some drawbacks. PIN Diodes work well when properly biased. However, the necessary bias current to limit harmonic generation can lead to reduced standby and talk times. MEMS technology is in theory the best solution to eliminate harmonic and current consumption issues. However, currently devices are generally unavailable and highly sensitive to ESD. GaAs switches currently show the most promise. They have insertion loss of around 0.3 to 0.5 dB. The use of such structures furthermore adds to the cost of the product and require additional power, which it is necessary to keep as low as possible in a portable communication device. Since switching between some bands is only required very seldom, like for instance when travelling from Europe to USA, the use of a fast switching, which electrically matched structures provide, is not an important factor.
Embodiments of the present invention solve the problem of providing an in-built antenna for a portable communication device, which requires little space and allows radiation in different frequency bands while keeping the efficiency of the different bands high.
According to some embodiments, an antenna arrangement is provided for a portable communication device, which requires little space and allows radiation in different frequency bands while keeping the efficiency of the different bands high.
According to a first aspect of the present invention, an antenna arrangement is provided in the interior of a portable communication device, the antenna arrangement comprising:
A second aspect of the present invention is directed towards an antenna arrangement including the features of the first aspect, further comprising a second radiating antenna element dimensioned for radiation in a third frequency band.
A third aspect of the present invention is directed towards an antenna arrangement including the features of the second aspect, wherein the first mechanically movable extension element is in proximity of the second radiating antenna element in one of the positions for aiding radiation of the second radiating antenna element.
A fourth aspect of the present invention is directed towards an antenna arrangement including the features of the second aspect, wherein the first mechanically movable extension element is in contact with the second radiating antenna element in one of the positions.
A fifth aspect of the present invention is directed towards an antenna arrangement including the features of the second aspect, further comprising a second mechanically movable extension element, movable between at least two different fixed positions, being connected to the second radiating antenna element in at least one of the positions for radiating together with the second radiating antenna element, which extension element when being moved from one position to another adjusts the electrical length of the combined second radiating antenna and second extension element for enhancing radiation in a fourth frequency band.
A sixth aspect of the present invention is directed towards an antenna arrangement including the features of the fifth aspect, wherein the two movable extension elements are joined to each other for simultaneous movement between different positions.
A seventh aspect of the present invention is directed towards an antenna arrangement including the features of the first aspect, wherein the first radiating antenna element is provided with two sections of differing lengths both provided adjacent a feeding section of the antenna arrangement and the mechanically movable extension element in one position bridges a gap between one such section and said feeding section.
An eighth aspect of the present invention is directed towards an antenna arrangement including the features of the first aspect, wherein the antenna arrangement is a PIFA antenna arrangement.
A ninth aspect of the present invention is directed towards an antenna arrangement including the features of the first aspect, wherein the mechanically movable extension element has a capacitive connection to radiating antenna elements.
A tenth aspect of the present invention is directed towards an antenna arrangement including the features of the first aspect, wherein the mechanically movable extension element has an electrical connection to radiating antenna elements.
According to some embodiments of the present invention, a portable communication device is provided having an antenna arrangement that requires little space and allows radiation in different frequency bands while keeping the efficiency of the different bands high.
According to an eleventh aspect of the present invention, a portable communication device is provided comprising in its interior:
A twelfth aspect of the present invention is directed towards a portable communication device including the features of the eleventh aspect, wherein the antenna arrangement further comprises a second radiating antenna element dimensioned for radiation in a third frequency band.
A thirteenth aspect of the present invention is directed towards a portable communication device including the features of the twelfth aspect, wherein the first mechanically movable extension element is in proximity of the second radiating antenna element in one of the positions for aiding radiation of the second radiating antenna element.
A fourteenth aspect of the present invention is directed towards a portable communication device including the features of the twelfth aspect, wherein the first mechanically movable extension element is in contact with the second radiating antenna element in one of the positions.
A fifteenth aspect of the present invention is directed towards a portable communication device including the features of the twelfth aspect, wherein the antenna arrangement further comprises a second mechanically movable extension element, movable between at least two different fixed positions, being connected to the second radiating antenna element in at least one of the positions for radiating together with the second radiating antenna element, which extension element when being moved from one position to another adjusts the electrical length of the combined second radiating antenna and second extension element for enhancing radiation in a fourth frequency band.
A sixteenth aspect of the present invention is directed towards a portable communication device including the features of the fifteenth aspect, wherein the two movable extension elements are joined to each other for simultaneous movement between different positions.
A seventeenth aspect of the present invention is directed towards a portable communication device including the features of the eleventh aspect, wherein the first radiating antenna element is provided with two sections of differing lengths both provided adjacent a feeding section of the antenna arrangement and the mechanically movable extension element in one position bridges a gap between one such section and said feeding section.
An eighteenth aspect of the present invention is directed towards a portable communication device including the features of the eleventh aspect, wherein all movable extension elements are connected to an actuating unit, which may be actuated by a user of the device.
A nineteenth aspect of the present invention is directed towards a portable communication device including the features of the eighteenth aspect, wherein the actuating unit is provided under the casing of the device for stopping a user from actuating said extension element.
A twentieth aspect of the present invention is directed towards a portable communication device including the features of the eighteenth aspect, wherein the actuating unit is provided on a surface of the portable communication device that is accessible to a user of the device.
A twenty-first aspect of the present invention is directed towards a portable communication device including the features of the eleventh aspect, wherein the antenna arrangement is a PIFA antenna arrangement.
A twenty-second aspect of the present invention is directed towards a portable communication device including the features of the eleventh aspect, wherein the mechanically movable extension element has a capacitive connection to radiating elements.
A twenty-third aspect of the present invention is directed towards a portable communication device including the features of the eleventh aspect, wherein the mechanically movable extension element has an electrical connection to radiating elements.
A twenty-fourth aspect of the present invention is directed towards a portable communication device including the features of the eleventh aspect, wherein it is a cellular phone.
According to embodiments of the present invention, multiband functionality is provided in a limited size antenna arrangement having a limited number of radiating antenna elements. Thus the antenna arrangement is small. The efficiencies of the different bands are furthermore kept high. According to some embodiments, the antenna arrangement also has low losses and is cheap to produce, which gives a low additional cost to the end product. There may be no power consumption associated with the extension element, which is also important for portable communication devices that are battery powered.
It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components, but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.
The present invention will now be described in more detail in relation to the enclosed drawings, in which:
a and b schematically show an antenna arrangement according to a first embodiment of the present invention provided with a mechanically movable extension element, which has been moved between two positions,
a and b schematically show an antenna arrangement according to a second embodiment of the present invention provided with a mechanically movable extension element, which has been moved between two positions,
a and b schematically show an antenna arrangement according to a third embodiment of the present invention provided with two mechanically movable extension elements, which have been moved between two positions, and
a–d schematically show an antenna arrangement according to a fourth embodiment of the present invention provided with a mechanically movable extension element, which has been moved between four positions.
A portable communication device according to embodiments of the invention will now be described in relation to a cellular phone. The phone may be a so-called stick-type phone, but can be other types of phones, like clam-shell phones or slider phones. The portable communication device can also be another type of device, like a communication module, a PDA or any other type of portable device communicating with radio waves.
The antenna arrangement 20 according to a first embodiment of the present invention is schematically shown in
According to embodiments of the present invention there is furthermore provided a first mechanically movable extension element 34 in the form of a plate of suitable metal (like copper). The extension element is made to turn between a first and a second position around a rotation point 35. In a first position, which is depicted in
The extension element 34 may be provided on a piece of plastic material. In order to provide turning round the turning point, the plastic material may be fastened via a pivot point to the phone. It should also be realised that the two positions may be fixed. Then is not possible to let the extension element take any position in-between or beyond these points. The reason for this is that this might be necessary to obtain the enhanced multiband functionality. The extension element is furthermore preferably capacitively connected to the first radiating antenna element in the first position. It is however possible also with an electrical connection, but then normally gold contacts are needed which makes the device unnecessarily expensive.
The extension element 32 may furthermore be connected to the actuating unit, which may consist of a lever, a button or any other suitable unit that may be actuated by the user for selecting the first or the second position of the extension element 34. This actuating unit may be provided on the exterior of the phone, for instance on the top side as is shown in
It might furthermore be suitable to place the actuating unit in the interior of the phone inside the casing, out of reach of the user, so that he cannot switch it himself. In this case the user would have to go to a service point in order for a serviceman to change position of the extension element.
There are a number of possible variations that can be made of the present invention. A first is shown in a second embodiment in
It is possible to provide embodiments of the present invention without a parasitic element. A third embodiment of the present invention, shown in
A fourth embodiment is shown in
It should be realised that the extension elements of the second, third and fourth embodiments may be connected to the previously described actuating unit.
Antenna arrangements according to embodiments of the invention may have several advantages. The antenna arrangement can provide multiband functionality in a limited size antenna arrangement having a limited number of radiating antenna elements. Thus the antenna arrangement is small. The efficiencies of the different bands can be kept high. The antenna arrangement can also have low losses. The antenna arrangement may be cheap to produce, which gives a low additional cost to the end product. Furthermore there may be no power consumption associated with the extension element, which is also important for portable communication devices that are battery powered. Embodiments of the present invention furthermore may provide high gain if correctly tuned. In general, those variants which have fewer bands in a given state may have higher gain for a set volume. Accordingly, the antenna arrangements according to the third and fourth embodiments shown in
A number of ways in which the present invention may be varied have been described. Several others exist. The invention can for instance be applied on other bands such as UMTS. For this reason there may also be provided more radiating antenna elements. Indeed, the bands mentioned are mere examples of bands where the invention can be used. The number of extension elements can be varied all according to how many antenna elements are to have their lengths varied. It is for instance possible to vary the first embodiment through extending the first radiating antenna element in the first position and to extend the second radiating antenna element in the second position or to only extend the second radiating antenna element and not the first. This may be combined with removal of the parasitic element or adding of a parasitic element to the first radiating antenna element. In the second embodiment it is for instance possible to provide shortening of the second radiating antenna element, either instead of or in addition to shortening of the first radiating antenna element. It is also possible to provide gaps between both the first and second section of the first radiating antenna element and make the extension element bridge one gap in a first position and the other gap in the other position. The first and second sections need not be parallel, what is important is that one is longer than the other. In the third embodiment it is for instance possible to extend both the first and second radiating antenna elements simultaneously. In order to this, the two extending elements may be actuated separately. In the fourth embodiment there may be provided more positions and then also more positions relating to extending the second radiating antenna element. The extending elements may also be provided either with turning or sliding movement and be capacitively or electrically connected to radiating antenna elements.
The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the invention.
Number | Name | Date | Kind |
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4914714 | Tamura | Apr 1990 | A |
6753827 | Oshiyama et al. | Jun 2004 | B2 |
Number | Date | Country | |
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20070115186 A1 | May 2007 | US |